Magnetic head for perpendicular magnetic recording

ABSTRACT

A magnetic head comprises a pole layer, a shield layer, a gap layer disposed between the pole layer and the shield layer, and a coil. The shield layer incorporates: a first layer disposed on the gap layer; a second layer disposed on the first layer; and a third layer disposed on the second layer. The first layer has an end face located in a medium facing surface. An end face of each of the second and third layers closer to the medium facing surface is located at a distance from the medium facing surface. A first nonmagnetic layer is disposed around the first layer. A second nonmagnetic layer is disposed between the medium facing surface and the end face of the second layer closer to the medium facing surface.

This is a Division of application Ser. No. 11/289,526 filed Nov. 30,2005. The disclosure of the prior application is hereby incorporated byreference herein in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a magnetic head for perpendicularmagnetic recording that is used for writing data on a recording mediumby means of a perpendicular magnetic recording system and to a method ofmanufacturing such a magnetic head.

2. Description of the Related Art

The recording systems of magnetic read/write devices include alongitudinal magnetic recording system wherein signals are magnetized inthe direction along the surface of the recording medium (thelongitudinal direction) and a perpendicular magnetic recording systemwherein signals are magnetized in the direction orthogonal to thesurface of the recording medium. It is known that the perpendicularmagnetic recording system is harder to be affected by thermalfluctuation of the recording medium and capable of implementing higherlinear recording density, compared with the longitudinal magneticrecording system.

Like magnetic heads for longitudinal magnetic recording, magnetic headsfor perpendicular magnetic recording typically used have a structure inwhich a reproducing (read) head having a magnetoresistive element (thatmay be hereinafter called an MR element) for reading and a recording(write) head having an induction-type electromagnetic transducer forwriting are stacked on a substrate. The write head comprises a polelayer that produces a magnetic field in the direction orthogonal to thesurface of the recording medium.

For the perpendicular magnetic recording system, it is an improvement inrecording medium and an improvement in write head that mainlycontributes to an improvement in recording density. It is a reduction intrack width and an improvement in write characteristics that isparticularly required for the write head to achieve higher recordingdensity. On the other hand, a reduction in track width causesdegradation in the write characteristics such as an overwrite propertythat is a parameter indicating an overwriting capability. It istherefore required to achieve better write characteristics as the trackwidth is reduced.

A magnetic head used for a magnetic disk drive such as a hard disk driveis typically provided in a slider. The slider has a medium facingsurface that faces toward a recording medium. The medium facing surfacehas an air-inflow-side end and an air-outflow-side end. The sliderslightly flies over the surface of the recording medium by means of theairflow that comes from the air-inflow-side end into the space betweenthe medium facing surface and the recording medium. The magnetic head istypically disposed near the air-outflow-side end of the medium facingsurface of the slider. In a magnetic disk drive the magnetic head isaligned through the use of a rotary actuator, for example. In this case,the magnetic head moves over the recording medium along a circular orbitcentered on the center of rotation of the rotary actuator. In such amagnetic disk drive, a tilt called a skew of the magnetic head iscreated with respect to the tangent of the circular track, in accordancewith the position of the magnetic head across the tracks.

In a magnetic disk drive of the perpendicular magnetic recording systemthat exhibits a better capability of writing on a recording medium thanthe longitudinal magnetic recording system, in particular, if theabove-mentioned skew is created, problems arise, such as a phenomenon inwhich data stored on an adjacent track is erased when data is written ona specific track (that is hereinafter called adjacent track erasing) orunwanted writing is performed between adjacent two tracks. To achievehigher recording density, it is required to suppress adjacent trackerasing. Unwanted writing between adjacent two tracks affects detectionof servo signals for alignment of the magnetic head and thesignal-to-noise ratio of a read signal.

A technique is known for preventing the problems resulting from the skewas described above, as disclosed in U.S. Patent Application PublicationNo. US2003/0151850 A1 and U.S. Pat. No. 6,504,675 B1, for example.According to this technique, the end face of the pole layer located inthe medium facing surface is made to have a shape in which the sidelocated backward along the direction of travel of the recording medium(that is, the side located closer to the air inflow end of the slider)is shorter than the opposite side.

As a magnetic head for perpendicular magnetic recording, a magnetic headcomprising the pole layer and a shield is known, as disclosed in U.S.Pat. No. 4,656,546, for example. In the medium facing surface of thismagnetic head, an end face of the shield is located forward of the endface of the pole layer along the direction of travel of the recordingmedium with a specific small space therebetween. Such a magnetic headwill be hereinafter called a shield-type head. In the shield-type headthe shield prevents a magnetic flux from reaching the recording medium,the flux being generated from the end face of the pole layer andextending in directions except the direction orthogonal to the surfaceof the recording medium. The shield-type head achieves a furtherimprovement in linear recording density.

Reference is now made to FIG. 32 to describe a basic configuration ofthe shield-type head. FIG. 32 is a cross-sectional view of the main partof an example of the shield-type head. The shield-type head comprises: amedium facing surface 100 that faces toward a recording medium; a coil101 for generating a field corresponding to data to be written on themedium; a pole layer 102 having an end located in the medium facingsurface 100, allowing a magnetic flux corresponding to the fieldgenerated by the coil 101 to pass, and generating a write magnetic fieldfor writing the data on the medium by means of the perpendicularmagnetic recording system; a shield layer 103 having an end located inthe medium facing surface 100 and having a portion located away from themedium facing surface 100 and coupled to the pole layer 102; a gap layer104 provided between the pole layer 102 and the shield layer 103; and aninsulting layer 105 covering the coil 101. An insulating layer 106 isdisposed around the pole layer 102. The shield layer 103 is covered witha protection layer 107.

In the medium facing surface 100, the end of the shield layer 103 islocated forward of the end of the pole layer 102 along the direction Tof travel of the recording medium with a specific space created by thethickness of the gap layer 104. At least part of the coil 101 isdisposed between the pole layer 102 and the shield layer 103 andinsulated from the pole layer 102 and the shield layer 103.

The coil 101 is made of a conductive material such as copper. The polelayer 102 and the shield layer 103 are made of a magnetic material. Thegap layer 104 is made of an insulating material such as alumina (Al₂O₃).The insulating layer 105 is made of photoresist, for example.

In the head of FIG. 32 the gap layer 104 is disposed on the pole layer102 and the coil 101 is disposed on the gap layer 104. The coil 101 iscovered with the insulating layer 105. One of the ends of the insulatinglayer 105 closer to the medium facing surface 100 is located at adistance from the medium facing surface 100. In the region from themedium facing surface 100 to the end of the insulating layer 105 closerto the medium facing surface 100, the shield layer 103 faces toward thepole layer 102 with the gap layer 104 disposed in between. Throat heightTH is the length (height) of the portions of the pole layer 102 and theshield layer 103 facing toward each other with the gap layer 104disposed in between, the length being taken from the end closer to themedium facing surface 100 to the other end. The throat height THinfluences the intensity and distribution of the field generated fromthe pole layer 102 in the medium facing surface 100.

In the shield-type head as shown in FIG. 32, for example, it ispreferred to reduce the throat height TH to improve the overwriteproperty. It is required that the throat height TH be 0.1 to 0.3micrometer (μm), for example. When such a small throat height TH isrequired, the following two problems arise in the head of FIG. 32.

The first problem of the head of FIG. 32 is that it is difficult todefine the throat height TH with accuracy. The first problem will now bedescribed in detail. In the head of FIG. 32 the throat height TH isdefined by the thickness of a portion of the shield layer 103 locatedbetween the insulating layer 105 and the medium facing surface 100. Inaddition, the throat height TH is controlled by the depth to which themedium facing surface 100 is polished. However, the photoresistconstituting the insulating layer 105 has a relatively high thermalexpansion coefficient and is relatively soft. As a result, theinsulating layer 105 expands due to the heat produced when polishing isperformed. In addition, the portion of the shield layer 103 locatedbetween the insulating layer 105 and the medium facing surface 100 isthin, particularly when the throat height TH is small. Furthermore, theend face of the shield layer 103 is exposed in a large region in themedium facing surface. Because of these factors, particularly in thecase where the throat height TH is small, when the medium facing surface100 is polished, the insulating layer 105 expands and the end portion ofthe shield layer 103 located closer to the medium facing surface 100tends to protrude. Consequently, the thickness of the portion of theshield layer 103 located between the insulating layer 105 and the mediumfacing surface 100 varies when the medium facing surface 100 ispolished, which results in variations in throat height TH after themedium facing surface 100 is polished.

The second problem of the head of FIG. 32 is that, when the head isoperated, the insulating layer 105 expands due to the heat generated bythe coil 101, and the end portion of the shield layer 103 located closerto the medium facing surface 100 thereby protrudes. The protrusion ofthe end portion of the shield layer 103 when the head is operatedinduces collision of the slider with the recording medium.

OBJECT AND SUMMARY OF THE INVENTION

It is an object of the invention to provide a magnetic head forperpendicular magnetic recording having a structure in which a polelayer faces toward a shield layer with a gap layer disposed in between,the head being capable of defining the throat height with accuracy andsuppressing protrusion of an end portion of the shield layer locatedcloser to the medium facing surface resulting from the heat generated bythe coil, and to provide a method of manufacturing such a magnetic head.

A first magnetic head for perpendicular magnetic recording of theinvention comprises: a medium facing surface that faces toward arecording medium; a coil for generating a magnetic field correspondingto data to be written on the recording medium; a pole layer having anend face located in the medium facing surface, allowing a magnetic fluxcorresponding to the field generated by the coil to pass therethrough,and generating a write magnetic field for writing the data on therecording medium by means of a perpendicular magnetic recording system;a shield layer having an end face located in the medium facing surfaceand having a portion that is away from the medium facing surface andcoupled to the pole layer; and a gap layer made of a nonmagneticmaterial and disposed between the pole layer and the shield layer.

In the medium facing surface, the end face of the shield layer islocated forward of the end face of the pole layer along a direction oftravel of the recording medium with a specific space created by athickness of the gap layer. At least part of the coil is disposedbetween the pole layer and the shield layer and insulated from the polelayer and the shield layer. The end face of the pole layer located inthe medium facing surface has a side located adjacent to the gap layer,the side defining a track width. The shield layer incorporates: a firstlayer located adjacent to the gap layer and having the end face locatedin the medium facing surface; and a second layer located on a side ofthe first layer farther from the gap layer. The second layer has an endface closer to the medium facing surface that is located at a distancefrom the medium facing surface. The first magnetic head of the inventionfurther comprises: an insulating layer made of an insulating materialand disposed around the at least part of the coil; a first nonmagneticlayer made of a nonmagnetic material and disposed around the firstlayer; and a second nonmagnetic layer made of a nonmagnetic material anddisposed between the medium facing surface and the end face of thesecond layer closer to the medium facing surface.

In the first magnetic head of the invention, the end face of the secondlayer of the shield layer closer to the medium facing surface is notexposed in the medium facing surface. The first nonmagnetic layer isdisposed around the first layer of the shield layer. The secondnonmagnetic layer is disposed between the medium facing surface and theend face of the second layer closer to the medium facing surface. As aresult, according to the first magnetic head of the invention, it ispossible to suppress protrusion of the end portion of the shield layerlocated closer to the medium facing surface occurring due to expansionof the insulating layer disposed around the at least part of the coil.

In the first magnetic head of the invention, the first and secondnonmagnetic layers may be made of an inorganic insulating material.

In the first magnetic head of the invention, the at least part of thecoil may be located farther from the pole layer than a surface of thefirst layer farther from the pole layer.

In the first magnetic head of the invention, the shield layer mayfurther incorporate a third layer connected to the second layer anddisposed on a side of the at least part of the coil farther from thepole layer. In addition, the third layer may have an end face closer tothe medium facing surface that is located at a distance from the mediumfacing surface.

In the first magnetic head of the invention, the second layer mayinclude a portion located on a side of the at least part of the coilfarther from the pole layer.

The first magnetic head of the invention may further comprise anonmagnetic film made of a nonmagnetic material and disposed between thepole layer and the second layer. In addition, the nonmagnetic film mayhave an end closer to the medium facing surface that is located at adistance from the medium facing surface. In this case, the first layermay have a portion located between the nonmagnetic film and the secondlayer.

The first magnetic head of the invention may further comprise asubstrate on which the pole layer, the gap layer, the coil and theshield layer are stacked. In addition, the pole layer may incorporate: afirst portion having the end face located in the medium facing surface;and a second portion located farther from the medium facing surface thanthe first portion and having a thickness greater than that of the firstportion, and a surface of the first portion farther from the substratemay be located closer to the substrate than a surface of the secondportion farther from the substrate.

In the first magnetic head of the invention, the first layer may havetwo portions located at positions along the direction of width outsidethe end face located in the medium facing surface when seen from themedium facing surface, and an end face of each of the two portionscloser to the medium facing surface may be located at a distance fromthe medium facing surface.

In the first magnetic head of the invention, the first layer mayincorporate: a middle portion including a portion facing toward the polelayer with the gap layer disposed in between; and two side portionslocated at positions outside the middle portion along the direction ofwidth, and the second layer may be connected to the side portions, notconnected to the middle portion. In this case, the maximum length ofeach of the side portions taken in the direction orthogonal to themedium facing surface may be greater than the maximum length of themiddle portion taken in the direction orthogonal to the medium facingsurface.

A second magnetic head for perpendicular magnetic recording of theinvention comprises: a medium facing surface that faces toward arecording medium; a coil for generating a magnetic field correspondingto data to be written on the recording medium; a pole layer having anend face located in the medium facing surface, allowing a magnetic fluxcorresponding to the field generated by the coil to pass therethrough,and generating a write magnetic field for writing the data on therecording medium by means of a perpendicular magnetic recording system;a shield layer having an end face located in the medium facing surfaceand having a portion that is away from the medium facing surface andcoupled to the pole layer; and a gap layer made of a nonmagneticmaterial and disposed between the pole layer and the shield layer.

In the medium facing surface, the end face of the shield layer islocated forward of the end face of the pole layer along the direction oftravel of the recording medium with a specific space created by athickness of the gap layer. At least part of the coil is disposedbetween the pole layer and the shield layer and insulated from the polelayer and the shield layer. The end face of the pole layer located inthe medium facing surface has a side located adjacent to the gap layer,the side defining a track width. The shield layer incorporates: a firstlayer located adjacent to the gap layer and having the end face locatedin the medium facing surface; and a second layer located on a side ofthe first layer farther from the gap layer. The first layer has twoportions located at positions along the direction of width outside theend face located in the medium facing surface when seen from the mediumfacing surface, and an end face of each of the two portions closer tothe medium facing surface is located at a distance from the mediumfacing surface. The second magnetic head of the invention furthercomprises: an insulating layer made of an insulating material anddisposed around the at least part of the coil; and a nonmagnetic layermade of a nonmagnetic material and disposed around the first layer.

In the second magnetic head of the invention, the first layer of theshield layer has the two portions located at positions along thedirection of width outside the end face located in the medium facingsurface when seen from the medium facing surface, and the end face ofeach of the two portions closer to the medium facing surface is locatedat a distance from the medium facing surface. In addition, thenonmagnetic layer is disposed around the first layer. As a result,according to the second magnetic head of the invention, it is possibleto suppress protrusion of the end portion of the shield layer locatedcloser to the medium facing surface occurring due to expansion of theinsulating layer disposed around the at least part of the coil.

In the second magnetic head of the invention, the nonmagnetic layer maybe made of an inorganic insulating material.

In the second magnetic head of the invention, the at least part of thecoil may be located farther from the pole layer than a surface of thefirst layer farther from the pole layer.

The second magnetic head of the invention may further comprise anonmagnetic film made of a nonmagnetic material and disposed between thepole layer and the second layer. In addition, the nonmagnetic film mayhave an end closer to the medium facing surface that is located at adistance from the medium facing surface. In this case, the first layermay have a portion located between the nonmagnetic film and the secondlayer.

A method of manufacturing the first magnetic head for perpendicularmagnetic recording of the invention comprises the steps of: forming thepole layer; forming the gap layer on the pole layer; forming the firstlayer on the gap layer; forming the first nonmagnetic layer; forming thecoil; forming the insulating layer; forming the second layer on thefirst layer; and forming the second nonmagnetic layer.

The magnetic head may further comprise a nonmagnetic film made of anonmagnetic material and disposed between the pole layer and the secondlayer. In addition, the nonmagnetic film may have an end closer to themedium facing surface that is located at a distance from the mediumfacing surface, and the first layer may have a portion located betweenthe nonmagnetic film and the second layer. In this case, the method mayfurther comprise the step of forming the nonmagnetic film on the polelayer.

The magnetic head may further comprise a substrate on which the polelayer, the gap layer, the coil and the shield layer are stacked, and thepole layer may incorporate a first portion having the end face locatedin the medium facing surface, and a second portion located farther fromthe medium facing surface than the first portion and having a thicknessgreater than that of the first portion. In addition, a surface of thefirst portion farther from the substrate may be located closer to thesubstrate than a surface of the second portion farther from thesubstrate. In this case, the step of forming the pole layer of themethod of manufacturing the first magnetic head of the invention mayinclude the steps of: forming a magnetic layer that will be formed intothe pole layer by polishing and etching later; polishing a top surfaceof the magnetic layer; and etching a portion of the magnetic layer suchthat the first and second portions are formed and the magnetic layer isthereby formed into the pole layer.

In the method of manufacturing the first magnetic head of the invention,the first layer may have two portions located at positions along adirection of width outside the end face located in the medium facingsurface when seen from the medium facing surface, and an end face ofeach of the two portions closer to the medium facing surface may belocated at a distance from the medium facing surface.

In the method of manufacturing the first magnetic head of the invention,the first layer may incorporate: a middle portion including a portionfacing toward the pole layer with the gap layer disposed in between; andtwo side portions located at positions outside the middle portion alonga direction of width. In addition, the second layer may be connected tothe side portions, not connected to the middle portion. In this case,the maximum length of each of the side portions taken in the directionorthogonal to the medium facing surface may be greater than the maximumlength of the middle portion taken in the direction orthogonal to themedium facing surface.

A method of manufacturing the second magnetic head for perpendicularmagnetic recording of the invention comprises the steps of: forming thepole layer; forming the gap layer on the pole layer; forming the firstlayer on the gap layer; forming the nonmagnetic layer; forming the coil;forming the insulating layer; and forming the second layer on the firstlayer.

The magnetic head may further comprise a nonmagnetic film made of anonmagnetic material and disposed between the pole layer and the secondlayer. In addition, the nonmagnetic film may have an end closer to themedium facing surface that is located at a distance from the mediumfacing surface, and the first layer may have a portion located betweenthe nonmagnetic film and the second layer. In this case, the method ofmanufacturing the second magnetic head of the invention may furthercomprise the step of forming the nonmagnetic film on the pole layer.

According to the first magnetic head for perpendicular magneticrecording of the invention or the method of manufacturing the same, theend face of the second layer of the shield layer closer to the mediumfacing surface is not exposed in the medium facing surface. The firstnonmagnetic layer is disposed around the first layer of the shieldlayer. The second nonmagnetic layer is disposed between the mediumfacing surface and the end face of the second layer closer to the mediumfacing surface. As a result, according to the invention, it is possibleto suppress protrusion of the end portion of the shield layer locatedcloser to the medium facing surface occurring due to expansion of theinsulating layer disposed around at least part of the coil.Consequently, the invention makes it possible to define the throatheight with accuracy and to suppress protrusion of the end portion ofthe shield layer located closer to the medium facing surface resultingfrom the heat produced by the coil.

According to the second magnetic head for perpendicular magneticrecording of the invention or the method of manufacturing the same, thefirst layer of the shield layer has the two portions located atpositions along the direction of width outside the end face located inthe medium facing surface when seen from the medium facing surface, andthe end face of each of the two portions closer to the medium facingsurface is located at a distance from the medium facing surface. Inaddition, the nonmagnetic layer is disposed around the first layer. As aresult, according to the invention, it is possible to suppressprotrusion of the end portion of the shield layer located closer to themedium facing surface occurring due to expansion of the insulating layerdisposed around at least part of the coil. Consequently, the inventionmakes it possible to define the throat height with accuracy and tosuppress protrusion of the end portion of the shield layer locatedcloser to the medium facing surface resulting from the heat produced bythe coil.

Other and further objects, features and advantages of the invention willappear more fully from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating a portion of a magnetic headof a first embodiment of the invention in a neighborhood of the mediumfacing surface.

FIG. 2 is a cross-sectional view for illustrating the configuration ofthe magnetic head of the first embodiment of the invention.

FIG. 3 is a front view of the medium facing surface of the magnetic headof the first embodiment of the invention.

FIG. 4 is a top view of the pole layer of the magnetic head of the firstembodiment of the invention.

FIG. 5A and FIG. 5B are views for illustrating a step of a method ofmanufacturing the magnetic head of the first embodiment of theinvention.

FIG. 6A and FIG. 6B are views for illustrating a step that follows thestep shown in FIG. 5A and FIG. 5B.

FIG. 7A and FIG. 7B are views for illustrating a step that follows thestep shown in FIG. 6A and FIG. 6B.

FIG. 8A and FIG. 8B are views for illustrating a step that follows thestep shown in FIG. 7A and FIG. 7B.

FIG. 9A and FIG. 9B are views for illustrating a step that follows thestep shown in FIG. 8A and FIG. 8B.

FIG. 10A and FIG. 10B are views for illustrating a step that follows thestep shown in FIG. 9A and FIG. 9B.

FIG. 11A and FIG. 11B are views for illustrating a step that follows thestep shown in FIG. 10A and FIG. 10B.

FIG. 12A and FIG. 12B are views for illustrating a step that follows thestep shown in FIG. 11A and FIG. 11B.

FIG. 13A and FIG. 13B are views for illustrating a step that follows thestep shown in FIG. 12A and FIG. 12B.

FIG. 14A and FIG. 14B are views for illustrating a first modificationexample of the magnetic head of the first embodiment of the invention.

FIG. 15A and FIG. 15B are views for illustrating a second modificationexample of the magnetic head of the first embodiment of the invention.

FIG. 16A and FIG. 16B are views for illustrating a third modificationexample of the magnetic head of the first embodiment of the invention.

FIG. 17 is a perspective view illustrating a portion of a magnetic headof a second embodiment of the invention in a neighborhood of the mediumfacing surface.

FIG. 18 is a cross-sectional view for illustrating the configuration ofthe magnetic head of the second embodiment of the invention.

FIG. 19 is a front view of the medium facing surface of the magnetichead of the second embodiment of the invention.

FIG. 20A and FIG. 20B are views for illustrating a step of a method ofmanufacturing the magnetic head of the second embodiment of theinvention.

FIG. 21A and FIG. 21B are views for illustrating a step that follows thestep shown in FIG. 20A and FIG. 20B.

FIG. 22A and FIG. 22B are views for illustrating a step that follows thestep shown in FIG. 21A and FIG. 21B.

FIG. 23A and FIG. 23B are views for illustrating a step that follows thestep shown in FIG. 22A and FIG. 22B.

FIG. 24A and FIG. 24B are views for illustrating a step that follows thestep shown in FIG. 23A and FIG. 23B.

FIG. 25A and FIG. 25B are views for illustrating a step that follows thestep shown in FIG. 24A and FIG. 24B.

FIG. 26A and FIG. 26B are views for illustrating a first modificationexample of the magnetic head of the second embodiment of the invention.

FIG. 27A and FIG. 27B are views for illustrating a second modificationexample of the magnetic head of the second embodiment of the invention.

FIG. 28 is a perspective view illustrating a portion of a magnetic headof a third embodiment of the invention in a neighborhood of the mediumfacing surface.

FIG. 29 is a top view illustrating a portion of the shield layer of themagnetic head of the third embodiment of the invention.

FIG. 30 is a cross-sectional view illustrating a portion of a magnetichead of a fourth embodiment of the invention.

FIG. 31 is a top view illustrating the shield layer of the magnetic headof the fourth embodiment of the invention.

FIG. 32 is a cross-sectional view illustrating a main part of an exampleof the shield-type head.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment

Preferred embodiments of the invention will now be described in detailwith reference to the accompanying drawings. Reference is now made toFIG. 1 to FIG. 4 to describe the configuration of a magnetic head forperpendicular magnetic recording of a first embodiment of the invention.FIG. 1 is a perspective view illustrating a portion of the magnetic headof the first embodiment in a neighborhood of the medium facing surface.FIG. 2 is a cross-sectional view for illustrating the configuration ofthe magnetic head of the embodiment. FIG. 2 illustrates a cross sectionorthogonal to the medium facing surface and a surface of a substrate.The arrow indicated with T in FIG. 2 shows the direction of travel of arecording medium. FIG. 3 is a front view of the medium facing surface ofthe magnetic head of the embodiment. FIG. 4 is a top view of the polelayer of the magnetic head of the embodiment.

As shown in FIG. 2 and FIG. 3, the magnetic head for perpendicularmagnetic recording (hereinafter simply called the magnetic head) of theembodiment comprises: a substrate 1 made of a ceramic such as aluminumoxide and titanium carbide (Al₂O₃—TiC); an insulating layer 2 made of aninsulating material such as alumina (Al₂O₃) and disposed on thesubstrate 1; a bottom shield layer 3 made of a magnetic material anddisposed on the insulating layer 2; a bottom shield gap film 4 that isan insulating film disposed on the bottom shield layer 3; amagnetoresistive (MR) element 5 as a read element disposed on the bottomshield gap film 4; a top shield gap film 6 that is an insulating filmdisposed on the MR element 5; and a first top shield layer 7 made of amagnetic material and disposed on the top shield gap film 6.

The MR element 5 has an end that is located in the medium facing surface30 that faces toward a recording medium. The MR element 5 may be anelement made of a magneto-sensitive film that exhibits amagnetoresistive effect, such as an anisotropic magnetoresistive (AMR)element, a giant magnetoresistive (GMR) element, or a tunnelmagnetoresistive (TMR) element. The GMR element may be of acurrent-in-plane (CIP) type wherein a current used for detectingmagnetic signals is fed in the direction nearly parallel to the plane ofeach layer making up the GMR element, or may be of acurrent-perpendicular-to-plane (CPP) type wherein a current used fordetecting magnetic signals is fed in the direction nearly perpendicularto the plane of each layer making up the GMR element.

The magnetic head further comprises a nonmagnetic layer 81 and a secondtop shield layer 82 that are disposed on the first top shield layer 7one by one. The nonmagnetic layer 81 is made of a nonmagnetic materialsuch as alumina. The second top shield layer 82 is made of a magneticmaterial. The portions from the bottom shield layer 3 to the second topshield layer 82 make up the read head.

The magnetic head further comprises: an insulating layer 83 made of aninsulating material and disposed on the second top shield layer 82; acoil 9 disposed on the insulating layer 83; an insulating layer 10 madeof an insulating material and disposed around the coil 9 and in thespace between the respective adjacent turns of the coil 9; and aninsulating layer 11 made of an insulating material and disposed aroundthe insulating layer 10. The coil 9 is flat-whorl-shaped. The coil 9 andthe insulating layers 10 and 11 have flattened top surfaces. Theinsulating layers 83 and 11 are made of alumina, for example. Theinsulating layer 10 is made of photoresist, for example. The coil 9 ismade of a conductive material such as copper.

The magnetic head further comprises an encasing layer 12 made of anonmagnetic material and disposed on the flattened top surfaces of thecoil 9 and the insulating layers 10 and 11. The encasing layer 12 has agroove 12 a that opens in the top surface thereof and that accommodatesa pole layer described later. The encasing layer 12 may be made of aninsulating material such as alumina, silicon oxide (SiO_(x)), or siliconoxynitride (SiON), or a nonmagnetic metal material such as Ru, Ta, Mo,Ti, W, NiCu, NiB or NiPd.

The magnetic head further comprises a nonmagnetic metal layer 13 made ofa nonmagnetic metal material and disposed on the top surface of theencasing layer 12. The nonmagnetic metal layer 13 has an opening 13 athat penetrates, and the edge of the opening 13 a is located directlyabove the edge of the groove 12 a in the top surface of the encasinglayer 12. The nonmagnetic metal layer 13 may be made of any of Ta, Mo,W, Ti, Ru, Rh, Re, Pt, Pd, Ir, NiCr, NiP, NiPd, NiB, WSi₂, TaSi₂, TiSi₂,TiN, and TiW, for example.

The magnetic head further comprises a nonmagnetic film 14 made of anonmagnetic material, a polishing stopper layer 15 and the pole layer 16that are disposed in the groove 12 a of the encasing layer 12 and in theopening 13 a of the nonmagnetic metal layer 13. The nonmagnetic film 14is disposed to touch the surface of the groove 12 a. The pole layer 16is disposed apart from the surface of the groove 12 a. The polishingstopper layer 15 is disposed between the nonmagnetic film 14 and thepole layer 16. The polishing stopper layer 15 also functions as a seedlayer used for forming the pole layer 16 by plating. The pole layer 16incorporates: a first layer 161 located closer to the surface of thegroove 12 a; and a second layer 162 located farther from the surface ofthe groove 12 a. The first layer 161 may be omitted, however.

The nonmagnetic film 14 may be made of an insulating material or asemiconductor material, for example. The insulating material as thematerial of the nonmagnetic film 14 may be any of alumina, silicon oxide(SiO_(x)), and silicon oxynitride (SiON). The semiconductor material asthe material of the nonmagnetic film 14 may be polycrystalline siliconor amorphous silicon.

The polishing stopper layer 15 is made of a nonmagnetic conductivematerial. The material of the polishing stopper layer 15 may be the sameas that of the nonmagnetic metal layer 13.

Each of the first layer 161 and the second layer 162 is made of amagnetic metal material. The first layer 161 may be made of any ofCoFeN, CoNiFe, NiFe, and CoFe, for example. The second layer 162 may bemade of any of NiFe, CoNiFe and CoFe, for example.

The magnetic head further comprises: a nonmagnetic film 17 made of anonmagnetic material such as alumina and disposed on portions of the topsurfaces of the polishing stopper layer 15 and the pole layer 16; and agap layer 18 made of a nonmagnetic material and disposed on thepolishing stopper layer 15, the pole layer 16 and the nonmagnetic film17. The nonmagnetic film 17 has an end located closer to the mediumfacing surface 30 and this end is located at a distance from the mediumfacing surface 30. The nonmagnetic film 17 has a thickness of 0.1 to 0.3μm, for example. The nonmagnetic film 17 and the gap layer 18 each havean opening located at a distance from the medium facing surface 30. Thegap layer 18 may be made of an insulating material such as alumina or anonmagnetic metal material such as Ru, NiCu, Ta, W, NiB or NiPd.

The magnetic head further comprises a shield layer 20. The shield layer20 has: a first layer 20A disposed adjacent to the gap layer 18; asecond layer 20C disposed on a side of the first layer 20A farther fromthe gap layer 18; a yoke layer 20B disposed on a portion of the polelayer 16 where the openings of the nonmagnetic film 17 and the gap layer18 are formed; a coupling layer 20D disposed on the yoke layer 20B; anda third layer 20E disposed to couple the second layer 20C to thecoupling layer 20D. The first layer 20A, the yoke layer 20B, the secondlayer 20C, the coupling layer 20D and the third layer 20E are each madeof a magnetic material. These layers 20A to 20E may be made of any ofCoFeN, CoNiFe, NiFe and CoFe, for example.

The magnetic head further comprises a nonmagnetic layer 21 made of anonmagnetic material and disposed around the first layer 20A and theyoke layer 20B. The nonmagnetic layer 21 is made of an inorganicinsulating material such as alumina or coating glass. Alternatively, thenonmagnetic layer 21 may be made up of a layer of a nonmagnetic metalmaterial and a layer of an insulating material disposed thereon. In thiscase, the nonmagnetic metal material may be a refractory metal such asTa, Mo, Nb, W, Cr, Ru, or Cu.

The magnetic head further comprises: an insulating layer 22 disposed onregions of the top surfaces of the yoke layer 20B and the nonmagneticlayer 21 in which a coil 23 described later is disposed; the coil 23disposed on the insulating layer 22; and an insulating layer 24 disposedaround the coil 23 and in the space between the respective adjacentturns of the coil 23. The insulating layer 22 is made of alumina, forexample. The coil 23 is flat-whorl-shaped. A portion of the coil 23passes between the second layer 20C and the coupling layer 20D. The coil23 is made of a conductive material such as copper. The insulating layer24 is made of photoresist, for example.

The magnetic head further comprises: a nonmagnetic layer 25 made of anonmagnetic material and disposed around the second layer 20C and thecoupling layer 20D; and an insulating layer 26 disposed on the coil 23and the insulating layer 24. The second layer 20C, the coupling layer20D, the coil 23, the insulating layer 24, and the nonmagnetic layer 25have flattened top surfaces. The nonmagnetic layer 25 and the insulatinglayer 26 are made of an inorganic insulating material such as alumina.

The portions from the coil 9 to the third layer 20E of the shield layer20 make up the write head. The magnetic head further comprises aprotection layer 27 made of a nonmagnetic material and formed to coverthe shield layer 20. The protection layer 27 is made of an inorganicinsulating material such as alumina.

As described so far, the magnetic head of the embodiment comprises themedium facing surface 30 that faces toward a recording medium, the readhead, and the write head. The read head and the write head are stackedon the substrate 1. The read head is located backward along thedirection T of travel of the recording medium (that is, located closerto the air inflow end of the slider). The write head is located forwardalong the direction T of travel of the recording medium (that is,located closer to the air outflow end of the slider).

The read head comprises the MR element 5 as the read element, and thebottom shield layer 3 and the top shield layer 7 for shielding the MRelement 5. Portions of the bottom shield layer 3 and the top shieldlayer 7 that are located on a side of the medium facing surface 30 areopposed to each other, the MR element 5 being placed between theseportions. The read head further comprises: the bottom shield gap film 4disposed between the MR element 5 and the bottom shield layer 3; and thetop shield gap film 6 disposed between the MR element 5 and the topshield layer 7.

The write head comprises the coil 9, the encasing layer 12, thenonmagnetic metal layer 13, the nonmagnetic film 14, the polishingstopper layer 15, the pole layer 16, the nonmagnetic film 17, the gaplayer 18, the shield layer 20, the nonmagnetic layer 21, the coil 23,the insulating layer 24, and the nonmagnetic layer 25. The coils 9 and23 generate a magnetic field corresponding to data to be written on therecording medium. The insulating layer 24 is disposed around the coil 23and in the space between the respective adjacent turns of the coil 23.The coil 9 is not a component requisite for the write head and may beomitted. The nonmagnetic film 14 may be omitted.

The pole layer 16 has an end face located in the medium facing surface30. The pole layer 16 allows the magnetic flux corresponding to thefield generated by the coil 23 to pass therethrough and generates awrite magnetic field for writing the data on the medium by using theperpendicular magnetic recording system.

The nonmagnetic film 17 is disposed on portions of the top surfaces ofthe polishing stopper layer 15 and the pole layer 16. The gap layer 18is disposed on the polishing stopper layer 15, the pole layer 16 and thenonmagnetic film 17. The nonmagnetic film 17 has the end located closerto the medium facing surface 30 that is located at a distance from themedium facing surface 30.

The shield layer 20 has an end face located in the medium facing surface30, and has a portion located away from the medium facing surface 30 andcoupled to the pole layer 16.

In the medium facing surface 30, the end face of the shield layer 20 isdisposed forward of the end face of the pole layer 16 along thedirection T of travel of the recording medium with a specific spacecreated by the thickness of the gap layer 18. The thickness of the gaplayer 18 falls within a range of 30 to 60 nm inclusive, for example. Atleast part of the coil 23 is disposed between the pole layer 16 and theshield layer 20 and insulated from the pole layer 16 and the shieldlayer 20.

The pole layer 16 is disposed in the groove 12 a of the encasing layer12 and in the opening 13 a of the nonmagnetic metal layer 13 with thenonmagnetic film 14 and the polishing stopper layer 15 disposed betweenthe pole layer 16 and each of the groove 12 a and the opening 13 a. Thenonmagnetic film 14 has a thickness that falls within a range of 10 to40 nm inclusive, for example. However, the thickness of the nonmagneticfilm 14 is not limited to this range but may be of any other value,depending on the track width. The polishing stopper layer 15 has athickness that falls within a range of 30 to 100 nm inclusive, forexample.

The pole layer 16 incorporates: the first layer 161 located closer tothe surface of the groove 12 a; and the second layer 162 located fartherfrom the surface of the groove 12 a. The first layer 161 has a thicknessthat falls within a range of 0 to 100 nm inclusive, for example. Thefirst layer 161 having a thickness of 0 nm means that the first layer161 is not provided.

The shield layer 20 has: the first layer 20A disposed adjacent to thegap layer 18 and having the end face located in the medium facingsurface 30; the second layer 20C disposed on a side of the first layer20A farther from the gap layer 18; the yoke layer 20B disposed on theportion of the pole layer 16 where the opening of the gap layer 18 isformed; the coupling layer 20D disposed on the yoke layer 20B; and thethird layer 20E disposed to couple the second layer 20C to the couplinglayer 20D. The coil 23 is located farther from the pole layer 16 thanthe surface of the first layer 20A farther from the pole layer 16. Thesecond layer 20C is disposed between the medium facing surface 30 andthe at least part of the coil 23.

The first layer 20A has a portion located between the nonmagnetic film17 and the second layer 20C. Therefore, the bottom surface of the firstlayer 20A bends to face toward the top surfaces of the pole layer 16 andthe nonmagnetic film 17 with the gap layer 18 disposed in between. Thegap layer 18 bends along the bottom surface of the first layer 20A, too.

The nonmagnetic layer 21 is disposed around the first layer 20A. Thenonmagnetic layer 21 corresponds to the first nonmagnetic layer of theinvention. Each of the second layer 20C and the third layer 20E has anend face located closer to the medium facing surface 30. The end face ofeach of the second layer 20C and the third layer 20E is located at adistance from the medium facing surface 30. The nonmagnetic layer 25 isdisposed between the medium facing surface 30 and the end face of thesecond layer 20C closer to the medium facing surface 30. The nonmagneticlayer 25 corresponds to the second nonmagnetic layer of the invention.It is preferred that each of the nonmagnetic layers 21 and 25 have athermal expansion coefficient lower than that of the insulating layer24.

In the portion of the first layer 20A facing toward the pole layer 16with the nonmagnetic film 17 and the gap layer 18 disposed in between,the minimum distance between the end face located in the medium facingsurface 30 and the opposite end face falls within a range of 0.3 to 1.2μm inclusive, for example. In the portion of the second layer 20C facingtoward the pole layer 16 with the nonmagnetic film 17, the gap layer 18and the first layer 20A disposed in between, the minimum distancebetween the end face located closer to the medium facing surface 30 andthe opposite end face falls within a range of 0.2 to 0.8 μm inclusive,for example. The minimum value of a length of the region where the firstlayer 20A touches the second layer 20C, the length being taken in thedirection orthogonal to the medium facing surface 30, falls within arange of 0.1 to 0.5 μm inclusive, for example.

The first layer 20A and the yoke layer 28B have a thickness that fallswithin a range of 0.2 to 0.6 μm inclusive, for example. The second layer20C and the coupling layer 20D have a thickness that falls within arange of 1.5 to 2.5 μm inclusive, for example. The third layer 20E has athickness that falls within a range of 0.5 to 2.0 μm inclusive, forexample. The coil 23 has a thickness that is equal to or smaller thanthe thickness of the second layer 20C and that falls within a range of1.5 to 2.5 μm inclusive, for example.

The end face of the first layer 20A located in the medium facing surface30 has a width equal to or greater than the track width. The maximumwidth of each of the second layer 20C and the third layer 20E is equalto or greater than the maximum width of the first layer 20A.

Reference is now made to FIG. 3 and FIG. 4 to describe the shape of thepole layer 16 in detail. As shown in FIG. 4, the pole layer 16incorporates a track width defining portion 16A and a wide portion 16B.The track width defining portion 16A has an end face located in themedium facing surface 30. The wide portion 16B is located farther fromthe medium facing surface 30 than the track width defining portion 16Aand has a width greater than the width of the track width definingportion 16A. The width of the track width defining portion 16A does notchange in accordance with the distance from the medium facing surface30. The wide portion 16B is equal in width to the track width definingportion 16A at the interface with the track width defining portion 16A,and gradually increases in width as the distance from the medium facingsurface 30 increases and then maintains a specific width to the end ofthe wide portion 16B. In the embodiment the track width defining portion16A is a portion of the pole layer 16 from the end face located in themedium facing surface 30 to the point at which the width of the polelayer 16 starts to increase. Here, the length of the track widthdefining portion 16A taken in the direction orthogonal to the mediumfacing surface 30 is called a neck height NH. The neck height NH fallswithin a range of 0.1 to 0.3 μm inclusive, for example.

As shown in FIG. 3, the end face of the pole layer 16 located in themedium facing surface 30 has: a first side A1 closest to the substrate1; a second side A2 adjacent to the gap layer 18; a third side A3connecting an end of the first side A1 to an end of the second side A2;and a fourth side A4 connecting the other end of the first side A1 tothe other end of the second side A2. The second side A2 defines thetrack width. The width of the end face of the pole layer 16 located inthe medium facing surface 30 decreases as the distance from the firstside A1 decreases. Each of the third side A3 and the fourth side A4forms an angle that falls within a range of 5 to 15 degrees inclusive,for example, with respect to the direction orthogonal to the top surfaceof the substrate 1. The length of the second side A2, that is, the trackwidth, falls within a range of 0.05 to 0.20 μm inclusive, for example.The thickness of the pole layer 16 falls within a range of 0.15 to 0.35μm inclusive, for example.

Throat height TH is the distance between the medium facing surface 30and one of two points that is closer to the medium facing surface 30,wherein one of the two points is the one at which the space between thepole layer 16 and the shield layer 20 starts to increase when seen fromthe medium facing surface 30, and the other of the points is the one atwhich the gap layer 18 first bends when seen from the medium facingsurface 30. In the embodiment, these two points coincide with eachother, so that the throat height TH is the distance between the mediumfacing surface 30 and these points. The throat height TH falls within arange of 0.05 to 0.3 μm inclusive, for example.

Reference is now made to FIG. 5A to FIG. 13A and FIG. 5B to FIG. 13B todescribe a method of manufacturing the magnetic head of the embodiment.FIG. 5A to FIG. 13A are cross-sectional views of layered structuresobtained in manufacturing process of the magnetic head orthogonal to themedium facing surface and the substrate. FIG. 5B to FIG. 13B show crosssections of portions of the layered structures near the medium facingsurface, the cross sections being parallel to the medium facing surface.The portions closer to the substrate 1 than the encasing layer 12 areomitted in FIG. 5A to FIG. 13A and FIG. 5B to FIG. 13B.

According to the method of manufacturing the magnetic head of theembodiment, as shown in FIG. 2, the insulating layer 2, the bottomshield layer 3 and the bottom shield gap film 4 are first formed one byone on the substrate 1. Next, the MR element 5 and leads (not shown)connected to the MR element 5 are formed on the bottom shield gap film4. Next, the top shield gap film 6 is formed to cover the MR element 5and the leads. Next, the top shield layer 7, the nonmagnetic layer 81,the second top shield layer 82, and the insulating layer 83 are formedone by one on the top shield gap film 6. Next, the coil 9 and theinsulating layers 10 and 11 are formed on the insulating layer 83. Next,the top surfaces of the coil 9 and the insulating layers 10 and 11 areflattened by chemical mechanical polishing (hereinafter referred to asCMP), for example.

FIG. 5A and FIG. 5B illustrate the following step. In the step, first, anonmagnetic layer 12P is formed on the flattened top surfaces of thecoil 9 and the insulating layers 10 and 11. The groove 12 a will beformed in the nonmagnetic layer 12P and the nonmagnetic layer 12P willbe thereby formed into the encasing layer 12 later. Next, thenonmagnetic metal layer 13 made of a nonmagnetic metal material isformed by sputtering, for example, on the nonmagnetic layer 12P. Thenonmagnetic metal layer 13 has a thickness that falls within a range of20 to 100 nm inclusive, for example.

Next, a photoresist layer having a thickness of 1.0 μm, for example, isformed on the nonmagnetic metal layer 13. The photoresist layer is thenpatterned to form a mask 31 for making the groove 12 a of the encasinglayer 12. The mask 31 has an opening having a shape corresponding to thegroove 12 a.

Next, the nonmagnetic metal layer 13 is selectively etched, using themask 31. The opening 13 a that penetrates is thereby formed in thenonmagnetic metal layer 13. The opening 13 a has a shape correspondingto the plane geometry of the pole layer 16 to be formed later.Furthermore, a portion of the nonmagnetic layer 12P exposed from theopening 13 a of the nonmagnetic metal layer 13 is selectively etched soas to form the groove 12 a in the nonmagnetic layer 12P. The mask 31 isthen removed. The nonmagnetic layer 12P is formed into the encasinglayer 12 by forming the groove 12 a therein. The edge of the opening 13a of the nonmagnetic metal layer 13 is located directly above the edgeof the groove 12 a located in the top surface of the encasing layer 12.

The etching of each of the nonmagnetic metal layer 13 and thenonmagnetic layer 12P is performed by reactive ion etching or ion beametching, for example. The etching for forming the groove 12 a in thenonmagnetic layer 12P is performed such that the walls of the groove 12a corresponding to both sides of the track width defining portion 16A ofthe pole layer 16 each form an angle that falls within a range of 5 to15 degrees inclusive, for example, with respect to the directionorthogonal to the top surface of the substrate 1.

FIG. 6A and FIG. 6B illustrate the following step. In the step, first,the nonmagnetic film 14 is formed on the entire top surface of thelayered structure. The nonmagnetic film 14 is formed in the groove 12 aof the encasing layer 12, too. The nonmagnetic film 14 is formed bysputtering or chemical vapor deposition (hereinafter referred to asCVD), for example. It is possible to control the thickness of thenonmagnetic film 14 with precision. If the nonmagnetic film 14 is formedby CVD, it is preferred to employ a method called ‘atomic layer CVD’(ALCVD) in which formation of a single atomic layer is repeated. In thiscase, it is possible to control the thickness of the nonmagnetic film 14with higher precision. When ALCVD is employed to form the nonmagneticfilm 14, it is preferable to use alumina, in particular, as the materialof the nonmagnetic film 14. If the nonmagnetic film 14 is made of asemiconductor material, it is preferred to form the nonmagnetic film 14by ALCVD at a low temperature (around 200° C.) or by low-pressure CVD ata low temperature. The semiconductor material as the material of thenonmagnetic film 14 is preferably undoped polycrystalline silicon oramorphous silicon.

Next, the polishing stopper layer 15 is formed on the entire top surfaceof the layered structure by sputtering or ALCVD, for example. Thepolishing stopper layer 15 is formed in the groove 12 a of the encasinglayer 12, too. The polishing stopper layer 15 indicates the level atwhich polishing of the polishing step to be performed later is stopped.

Next, a first magnetic layer 161P to be the first layer 161 of the polelayer 16 is formed on the entire top surface of the layered structure.The first magnetic layer 161P is formed by sputtering or ion beamdeposition (hereinafter referred to as IBD), for example. If the firstmagnetic layer 161P is formed by sputtering, it is preferred to employcollimation sputtering or long throw sputtering. Since the first layer161 may be omitted as previously described, it is not absolutelynecessary to form the first magnetic layer 161P.

FIG. 7A and FIG. 7B illustrate the following step. In the step, first, asecond magnetic layer to be the second layer 162 of the pole layer 16 isformed on the first magnetic layer 161P. The second magnetic layer isformed such that the top surface thereof is located higher than the topsurfaces of the nonmagnetic metal layer 13, the nonmagnetic film 14 andthe polishing stopper layer 15. The second magnetic layer is formed byframe plating, for example. In this case, the first magnetic layer 161Pis used as an electrode for plating. If the polishing stopper layer 15is made of a conductive material, the layer 15 is used as an electrodefor plating, too. The second magnetic layer may be formed by making anunpatterned plating layer and then patterning the plating layer throughetching.

Next, a coating layer not shown made of alumina, for example, and havinga thickness of 0.5 to 1.2 μm, for example, is formed on the entire topsurface of the layered structure. Next, the coating layer, the secondmagnetic layer and the first magnetic layer 161P are polished by CMP,for example, so that the polishing stopper layer 15 is exposed, and thetop surfaces of the polishing stopper layer 15, the first magnetic layer161P and the second magnetic layer are thereby flattened. As a result,the first magnetic layer 161P and the second magnetic layer are formedinto the first layer 161 and the second layer 162, respectively. If thecoating layer, the second magnetic layer and the first magnetic layer161P are polished by CMP, such a slurry is used that polishing isstopped when the polishing stopper layer 15 is exposed, such as analumina-base slurry.

Next, as shown in FIG. 8A and FIG. 8B, the nonmagnetic film 17 is formedby sputtering, for example, on the entire top surface of the layeredstructure.

FIG. 9A and FIG. 9B illustrate the following step. In the step, first, aphotoresist layer having a thickness of 1.0 μm, for example, is formedon the entire top surface of the layered structure. The photoresistlayer is then patterned to form a mask 32 for etching a portion of thenonmagnetic film 17. The distance between the medium facing surface 30and an end of the mask 32 closer to the medium facing surface 30 fallswithin a range of 0.1 to 0.3 μm inclusive, for example. Next, theportion of the nonmagnetic film 17 is etched by reactive ion etching,for example, using the mask 32. Next, the mask 32 is removed.

Next, as shown in FIG. 10A and FIG. 10B, the gap layer 18 is formed onthe entire top surface of the layered structure. The gap layer 18 isformed by sputtering or CVD, for example. If the gap layer 18 is formedby CVD, it is preferred to employ ALCVD. If the gap layer 18 is formedby ALCVD, it is preferred that the gap layer 18 be made of alumina. Thegap layer 18 formed by ALCVD exhibits a good step coverage. Therefore,it is possible to form the gap layer 18 that is uniform on the unevensurface by forming the gap layer 18 by ALCVD.

FIG. 11A and FIG. 11B illustrate the following step. In the step, first,portions of the gap layer 18 and the nonmagnetic film 17 that are awayfrom the medium facing surface 30 are selectively etched to formopenings in the gap layer 18 and the nonmagnetic film 17. Next, thefirst layer 20A is formed on the gap layer 18, and the yoke layer 20B isformed on a portion of the pole layer 16 where the openings of the gaplayer 18 and the nonmagnetic film 17 are formed. The first layer 20A andthe yoke layer 20B may be formed by frame plating or by making amagnetic layer through sputtering and then selectively etching themagnetic layer. Selective etching of the magnetic layer may be performedby, for example, making an alumina layer on the magnetic layer, making amask on the alumina layer by frame plating, and etching the aluminalayer and the magnetic layer using the mask.

FIG. 12A and FIG. 12B illustrate the following step. In the step, first,the nonmagnetic layer 21 is formed on the entire top surface of thelayered structure. Next, the nonmagnetic layer 21 is polished by CMP,for example, so that the first layer 20A and the yoke layer 20B areexposed, and the top surfaces of the first layer 20A, the yoke layer 20Band the nonmagnetic layer 21 are flattened.

Next, the insulating layer 22 is formed on regions of the top surfacesof the yoke layer 20B and the nonmagnetic layer 21 in which the coil 23will be disposed. Next, the coil 23 is formed by frame plating, forexample, such that at least part of the coil 23 is disposed on theinsulating layer 22.

FIG. 13A and FIG. 13B illustrate the following step. In the step, first,the second layer 20C and the coupling layer 20D are formed by frameplating, for example. Alternatively, the coil 23 may be formed after thesecond layer 20C and the coupling layer 20D are formed. Next, theinsulating layer 24 made of photoresist, for example, is selectivelyformed around the coil 23 and in the space between the respectiveadjacent turns of the coil 23. Next, the nonmagnetic layer 25 having athickness of 4 to 4.5 μm, for example, is formed on the entire topsurface of the layered structure. Next, the nonmagnetic layer 25 ispolished by CMP, for example, so that the second layer 20C, the couplinglayer 20D and the coil 23 are exposed, and the top surfaces of thesecond layer 20C, the coupling layer 20D, the coil 23, the insulatinglayer 24, and the nonmagnetic layer 25 are thereby flattened. Next, theinsulating layer 26 is formed on the coil 23, the insulating layer 24and the nonmagnetic layer 25. Next, the third layer 20E is formed byframe plating, for example, to complete the shield layer 20.

Next, the protection layer 27 is formed to cover the entire top surfaceof the layered structure. Wiring and terminals are then formed on theprotection layer 27, the substrate is cut into sliders, and the stepsincluding polishing of the medium facing surface 30 and fabrication offlying rails are performed. The magnetic head is thus completed.

The operation and effects of the magnetic head of the embodiment willnow be described. The magnetic head writes data on a recording medium byusing the write head and reads data written on the recording medium byusing the read head. In the write head the coil 23 generates a magneticfield that corresponds to the data to be written on the medium. The polelayer 16 and the shield layer 20 form a magnetic path through which amagnetic flux corresponding to the magnetic field generated by the coil23 passes. The pole layer 16 allows the flux corresponding to the fieldgenerated by the coil 23 to pass and generates a write magnetic fieldused for writing the data on the medium through the use of theperpendicular magnetic recording system. The shield layer 20 takes in adisturbance magnetic field applied from outside the magnetic head to themagnetic head. It is thereby possible to prevent erroneous writing onthe recording medium caused by the disturbance magnetic fieldintensively taken in into the pole layer 16.

According to the embodiment, in the medium facing surface 30, the endface of the shield layer 20 is located forward of the end face of thepole layer 16 along the direction T of travel of the recording medium(that is, located closer to the air outflow end of the slider) with aspecific small space created by the gap layer 18. The location of an endof the bit pattern written on the recording medium is determined by thelocation of the end of the pole layer 16 that is closer to the gap layer18 and located in the medium facing surface 30. The shield layer 20takes in a magnetic flux generated from the end face of the pole layer16 located in the medium facing surface 30 and extending in directionsexcept the direction orthogonal to the surface of the recording mediumso as to prevent the flux from reaching the recording medium. It isthereby possible to prevent a direction of magnetization of the bitpattern already written on the medium from being changed due to theeffect of the above-mentioned flux. According to the embodiment, animprovement in linear recording density is thus achieved.

According to the embodiment, the nonmagnetic layer 21 is disposed aroundthe first layer 20A of the shield layer 20. In addition, the end face ofthe second layer 20C of the shield layer 20 located closer to the mediumfacing surface 30 is not exposed in the medium facing surface 30, andthe nonmagnetic layer 25 is disposed between the medium facing surface30 and the end face of the second layer 20C located closer to the mediumfacing surface 30. As a result, according to the embodiment, it ispossible to make the area of the end face of the shield layer 20 exposedin the medium facing surface 30 smaller and to make the distance betweenthe medium facing surface 30 and the insulating layer 24 disposed aroundthe coil 23 greater, compared with the magnetic head of FIG. 32. It isthereby possible to suppress protrusion of the end portion of the shieldlayer 20 located closer to the medium facing surface 30 occurring inresponse to expansion of the insulating layer 24 disposed around thecoil 23. As a result, it is possible to define the throat height TH withaccuracy and to suppress protrusion of the end portion of the shieldlayer 20 located closer to the medium facing surface 30 resulting fromthe heat generated by the coil 23. This effect is particularlynoticeable if the nonmagnetic layers 21 and 25 are made of an inorganicinsulating material that is harder than the material of the insulatinglayer 24 (such as photoresist) or if the nonmagnetic layers 21 and 25have a thermal expansion coefficient smaller than that of the insulatinglayer 24. To make the most of the effect, it is preferred that the coil23 be located farther from the pole layer 16 than the surface of thefirst layer 20A farther from the pole layer 16.

According to the embodiment, the throat height TH is not defined by theend of the first layer 20A farther from the medium facing surface 30 butdefined by the point at which the gap layer 18 first bends when seenfrom the medium facing surface 30, that is, the point at which thebottom surface of the first layer 20A first bends when seen from themedium facing surface 30. As a result, it is possible to reduce thethroat height TH while the volume of the first layer 20A is sufficientlyincreased. It is thereby possible to further suppress protrusion of theend portion of the shield layer 20 located closer to the medium facingsurface 30 and to improve the overwrite property.

According to the embodiment, as shown in FIG. 2, the end face of thepole layer 16 located in the medium facing surface 30 has a width thatdecreases as the distance from the first side A1 decreases. It isthereby possible to prevent the problems resulting from the skew.

According to the embodiment, the pole layer 16 is disposed in the groove12 a of the encasing layer 12 made of a nonmagnetic material with thenonmagnetic film 14 and the polishing stopper layer 15 disposed betweenthe pole layer 16 and the groove 12 a. Consequently, the pole layer 16is smaller than the groove 12 a in width. It is thereby possible toeasily form the groove 12 a and to easily reduce the width of the polelayer 16 and the width of the top surface of the track width definingportion 16A that defines the track width, in particular. As a result,according to the embodiment, it is possible to easily implement thetrack width that is smaller than the minimum track width that can beformed by photolithography and to control the track width with accuracy.

MODIFICATION EXAMPLES

First to third modification examples of the embodiment will now bedescribed. FIG. 14A and FIG. 14B illustrate the first modificationexample. FIG. 14A shows a cross section of the main part of the magnetichead orthogonal to the medium facing surface and the substrate. FIG. 14Bshows a cross section of the main part of the magnetic head near themedium facing surface that is parallel to the medium facing surface. InFIG. 14A and FIG. 14B the portions closer to the substrate 1 than theencasing layer 12 are omitted.

The magnetic head of the first modification example comprises aninsulating layer 28 that covers at least part of the coil 23 in place ofthe insulating layer 24 of FIG. 2. The insulating layer 28 is made ofphotoresist, for example. The shield layer 20 of the first modificationexample comprises a second layer 20F in place of the second layer 20C,the coupling layer 20D and the third layer 20E of the FIG. 2. One of endfaces of the second layer 20F closer to the medium facing surface 30 islocated at a distance from the medium facing surface 30. The secondlayer 20F is disposed to couple the first layer 20A to the yoke layer20B. The second layer 20F includes a portion located on a side of the atleast part of the coil 23 covered with the insulating layer 28, the sidebeing opposite to the pole layer 16. The second layer 20F may be made ofany of CoFeN, CoNiFe, NiFe, and CoFe, for example. In the firstmodification example, the protection layer 27 is disposed between themedium facing surface 30 and the end face of the second layer 20F closerto the medium facing surface 30. The protection layer 27 of the firstmodification example corresponds to the second nonmagnetic layer of theinvention. It is preferred that the protection layer 27 has a thermalexpansion coefficient smaller than that of the insulating layer 28. Theremainder of configuration, function and effects of the magnetic head ofthe first modification example are similar to those of the magnetic headof FIG. 1 to FIG. 4.

FIG. 15A and FIG. 15B illustrate the second modification example. FIG.15A shows a cross section of the main part of the magnetic headorthogonal to the medium facing surface and the substrate. FIG. 15Bshows a cross section of the main part of the magnetic head near themedium facing surface that is parallel to the medium facing surface. InFIG. 15A and FIG. 15B the portions closer to the substrate 1 than theencasing layer 12 are omitted.

In the second modification example a coupling layer 20G is provided inplace of the yoke layer 20B of the first modification example. Thecoupling layer 20G is made of a material the same as that of the yokelayer 20B. The bottom surface of the coupling layer 20G touches the topsurface of the pole layer 16. The top surface of the coupling layer 20Gtouches the bottom surface of the second layer 20F. The coupling layer20G is disposed only in a region corresponding to the center of the coil23. The nonmagnetic film 17, the gap layer 18 and the nonmagnetic layer21 further extend to a region below at least part of the coil 23. Theremainder of configuration, function and effects of the magnetic head ofthe second modification example are similar to those of the magnetichead of the first modification example.

FIG. 16A and FIG. 16B illustrate the third modification example. FIG.16A shows a cross section of the main part of the magnetic headorthogonal to the medium facing surface and the substrate. FIG. 16Bshows a cross section of the main part of the magnetic head near themedium facing surface that is parallel to the medium facing surface. InFIG. 16A and FIG. 16B the portions closer to the substrate 1 than theencasing layer 12 are omitted.

In the third modification example each of the second layer 20C and thecoupling layer 20D has a width that decreases as the distance from thesubstrate 1 increases. Consequently, the distance between the mediumfacing surface 30 and the end face of the second layer 20C closer to themedium facing surface 30 increases as the distance from the substrate 1increases. The remainder of configuration, function and effects of themagnetic head of the third modification example are similar to those ofthe magnetic head of FIG. 1 to FIG. 4.

Second Embodiment

A magnetic head and a method of manufacturing the same of a secondembodiment of the invention will now be described. Reference is now madeto FIG. 17 to FIG. 19 to describe the configuration of the magnetic headof the second embodiment. FIG. 17 is a perspective view illustrating aportion of the magnetic head of the embodiment in a neighborhood of themedium facing surface. FIG. 18 is a cross-sectional view forillustrating the configuration of the magnetic head of the embodiment.FIG. 18 illustrates a cross section orthogonal to the medium facingsurface and a surface of a substrate. The arrow indicated with T in FIG.18 shows the direction of travel of a recording medium. FIG. 19 is afront view of the medium facing surface of the magnetic head of theembodiment.

In the second embodiment, as shown in FIG. 18, the pole layer 16incorporates: a first portion 16C having the end face located in themedium facing surface 30; and a second portion 16D located farther fromthe medium facing surface 30 than the first portion 16C and having athickness greater than that of the first portion 16C. The thickness ofthe first portion 16C does not change in accordance with the distancefrom the medium facing surface 30.

The location of the boundary between the first portion 16C and thesecond portion 16D may coincide with the location of the boundarybetween the track width defining portion 16A and the wide portion 16B,or may be located closer to or farther from the medium facing surface 30than the boundary between the track width defining portion 16A and thewide portion 16B. The distance from the medium facing surface 30 to theboundary between the first portion 16C and the second portion 16D fallswithin a range of 0.1 to 0.5 μm inclusive, for example. An example inwhich the location of the boundary between the first portion 16C and thesecond portion 16D coincides with the location of the boundary betweenthe track width defining portion 16A and the wide portion 16B will nowbe described.

A surface (a top surface) 16Ca of the first portion 16C farther from thesubstrate 1 is located closer to the substrate 1 than a surface (a topsurface) 16Da of the second portion 16D farther from the substrate 1.The second portion 16D has a front end face 16Db that couples thesurface 16Ca of the first portion 16C farther from the substrate 1 tothe surface 16Da of the second portion 16D farther from the substrate 1.The front end face 16Db may be nearly orthogonal to the top surface ofthe substrate 1. Here, the front end face 16Db nearly orthogonal to thetop surface of the substrate 1 means that the front end face 16Db formsan angle that falls within a range of 80 to 90 degrees inclusive withrespect to the top surface of the substrate 1. If the front end face16Db forms an angle that is equal to or greater than 80 degrees andsmaller than 90 degrees with respect to the top surface of the substrate1, each of the angle formed between the surfaces 16Ca and 16Db and theangle formed between the surfaces 16Da and 16Db is an obtuse angle.Alternatively, the front end face 16Db may be tilted with respect to thedirection orthogonal to the top surface of the substrate 1 such that, inthe region in which the front end face 16Db is located, the thickness ofthe pole layer 16 gradually increases as the distance from the mediumfacing surface 30 increases. In this case, the front end face 16Dbpreferably forms an angle that is equal to or greater than 30 degreesand smaller than 80 degrees with respect to the top surface of thesubstrate 1. The difference in level created between the surface 16Caand the surface 16Da falls within a range of 0.1 to 0.3 μm inclusive,for example.

An end of the nonmagnetic film 17 closer to the medium facing surface 30is located at a position corresponding to a corner portion formedbetween the surfaces 16Da and 16Db.

The shield layer 20 has a portion that is sandwiched between the frontend face 16Db and the medium facing surface 30 and that is located in aregion closer to the substrate 1 than the surface 16Da of the secondportion 16D farther from the substrate 1. To be specific, this portionis a portion of the first layer 20A of the shield layer 20 closer to thesubstrate 1 than the surface 16Da. An end of the yoke layer 20B of theshield layer 20 located closer to the medium facing surface 30 islocated farther from the medium facing surface 30 than the boundarybetween the surfaces 16Da and 16Db of the pole layer 16.

In the embodiment, the throat height TH is the distance between themedium facing surface 30 and the point at which the gap layer 18 firstbends when seen from the medium facing surface 30, that is, the distancebetween the medium facing surface 30 and the point at which the bottomsurface of the first layer 20A first bends when seen from the mediumfacing surface 30. The reason will now be described. In the region fromthe medium facing surface 30 to the point at which the gap layer 18first bends when seen from the medium facing surface 30, the fluxleakage between the pole layer 16 and the shield layer 20 is greater,compared with the flux leakage between the pole layer 16 and the shieldlayer 20 in any other region. Furthermore, it is the flux leakagebetween the pole layer 16 and the shield layer 20 in the region from themedium facing surface 30 to the point at which the gap layer 18 firstbends when seen from the medium facing surface 30 that contributes towriting of data. Therefore, it is appropriate that the throat height THis defined as the distance from the medium facing surface 30 to thepoint at which the gap layer 18 first bends when seen from the mediumfacing surface 30.

Reference is now made to FIG. 20A to FIG. 25A and FIG. 20B to FIG. 25Bto describe a method of manufacturing the magnetic head of theembodiment. FIG. 20A to FIG. 25A are cross-sectional views of layeredstructures obtained in manufacturing process of the magnetic headorthogonal to the medium facing surface and the substrate. FIG. 20B toFIG. 25B show cross sections of portions of the layered structures nearthe medium facing surface, the cross sections being parallel to themedium facing surface. The portions closer to the substrate 1 than theencasing layer 12 are omitted in FIG. 20A to FIG. 25A and FIG. 20B toFIG. 25B.

The method of manufacturing the magnetic head of the second embodimentincludes the steps up to the step shown in FIG. 7A and FIG. 7B that arethe same as those of the first embodiment. That is, the second magneticlayer 162P to be the second layer 162 of the pole layer 16 is formed onthe first magnetic layer 161P and then the coating layer, the secondmagnetic layer 162P and the first magnetic layer 161P are polished untilthe polishing stopper layer 15 is exposed. In the following step of thesecond embodiment, as shown in FIG. 20A and FIG. 20B, the nonmagneticfilm 17 is formed by sputtering, for example, on the entire top surfaceof the layered structure.

FIG. 21A and FIG. 21B illustrate the following step. In the step, first,a photoresist layer having a thickness of 1.0 μm, for example, is formedon the entire top surface of the layered structure. The photoresistlayer is then patterned to form a mask 32 for etching portions of themagnetic layers 161P and 162P and the nonmagnetic film 17. The distancebetween the medium facing surface 30 and an end of the mask 32 closer tothe medium facing surface 30 falls within a range of 0.1 to 0.3 μminclusive, for example. The mask 32 is located above the top surfaces ofthe magnetic layers 161P and 162P except the regions in which thesurface 16Ca and the front end face 16Db will be formed. Next, a portionof the nonmagnetic film 17 is etched by reactive ion etching, forexample, using the mask 32.

Next, as shown in FIG. 22A and FIG. 22B, the portions of the magneticlayers 161P and 162P are etched by ion beam etching, for example, usingthe mask 32. As a result, the surfaces 16Ca and 16Da and the front endface 16Db are formed on the top surfaces of the magnetic layers 161P and162P, and the magnetic layers 161P and 162P are thereby formed into thefirst layer 161 and the second layer 162, respectively. When theportions of the magnetic layers 161P and 162P are etched by ion beametching, the direction in which ion beams move should form an angle thatfalls within a range of 40 to 55 degrees inclusive, for example, withrespect to the top surface of the substrate 1. It is thereby possiblethat the front end face 16Db form an angle that falls within a range of80 to 90 degrees inclusive with respect to the top surface of thesubstrate 1. In addition, this etching is performed such that the secondside A2 of the end face of the pole layer 16 located in the mediumfacing surface 30 is disposed at a height that falls within the rangebetween the height at which the top surface of the nonmagnetic metallayer 13 as initially formed is located and the height at which thebottom surface thereof is located. Therefore, the nonmagnetic metallayer 13 serves as the reference that indicates the level at which thisetching is stopped. The portions of the magnetic layers 161P and 162Pare etched in the manner thus described, so that each of the track widthand the thickness of the pole layer 16 taken in the medium facingsurface 30 is controlled to be nearly uniform. It is thereby possible tocontrol the thickness of the pole layer 16 and the track width withprecision. Next, the mask 32 is removed.

Next, as shown in FIG. 23A and FIG. 23B, the gap layer 18 is formed onthe entire top surface of the layered structure. The material and theformation method of the gap layer 18 are the same as those of the firstembodiment.

FIG. 24A and FIG. 24B illustrate the following step. In the step, first,portions of the gap layer 18 and the nonmagnetic film 17 that are awayfrom the medium facing surface 30 are selectively etched to formopenings in the gap layer 18 and the nonmagnetic film 17. Next, thefirst layer 20A is formed on the gap layer 18, and the yoke layer 20B isformed on a portion of the pole layer 16 where the openings of the gaplayer 18 and the nonmagnetic film 17 are formed. The first layer 20A andthe yoke layer 20B are formed by a method the same as that of the firstembodiment.

FIG. 25A and FIG. 25B illustrate the following step. In the step, first,the nonmagnetic layer 21 is formed on the entire top surface of thelayered structure. Next, the nonmagnetic layer 21 is polished by CMP,for example, until the first layer 20A and the yoke layer 20B areexposed, and the top surfaces of the first layer 20A, the yoke layer 20Band the nonmagnetic layer 21 are thereby flattened. Next, the insulatinglayer 22 is formed on regions of the top surfaces of the yoke layer 20Band the nonmagnetic layer 21 in which the coil 23 will be disposed.Next, the coil 23 is formed by frame plating, for example, such that atleast part of the coil 23 is disposed on the insulating layer 22. Next,the second layer 20C and the coupling layer 20D are formed by frameplating, for example. Alternatively, the coil 23 may be formed after thesecond layer 20C and the coupling layer 20D are formed. Next, theinsulating layer 24 made of photoresist, for example, is selectivelyformed around the coil 23 and in the space between the respectiveadjacent turns of the coil 23. Next, the nonmagnetic layer 25 having athickness of 4 to 4.5 μm, for example, is formed on the entire topsurface of the layered structure. Next, the nonmagnetic layer 25 ispolished by CMP, for example, so that the second layer 20C, the couplinglayer 20D and the coil 23 are exposed, and the top surfaces of thesecond layer 20C, the coupling layer 20D, the coil 23, the insulatinglayer 24, and the nonmagnetic layer 25 are thereby flattened. Next, theinsulating layer 26 is formed on the coil 23, the insulating layer 24and the nonmagnetic layer 25. Next, the third layer 20E is formed byframe plating, for example, to complete the shield layer 20.

Next, the protection layer 27 is formed to cover the entire top surfaceof the layered structure. Wiring and terminals are then formed on theprotection layer 27, the substrate is cut into sliders, and the stepsincluding polishing of the medium facing surface 30 and fabrication offlying rails are performed. The magnetic head is thus completed.

According to the embodiment, the pole layer 16 incorporates the firstportion 16C and the second portion 16D. The first portion 16C has theend face located in the medium facing surface 30, and has a thicknessthat does not change in accordance with the distance from the mediumfacing surface 30. The second portion 16D is located farther from themedium facing surface 30 than the first portion 16C and has a thicknessgreater than that of the first portion 16C. The surface 16Ca of thefirst portion 16C farther from the substrate 1 is located closer to thesubstrate 1 than the surface 16Da of the second portion 16D farther fromthe substrate 1. The second portion 16D has the front end face 16Db thatcouples the surface 16Ca of the first portion 16C farther from thesubstrate 1 to the surface 16Da of the second portion 16D farther fromthe substrate 1. The end face of the pole layer 16 located in the mediumfacing surface 30 has the first side A1 closest to the substrate 1 andthe second side A2 opposite to the first side A1, and the second side A2defines the track width. The surface 16Da of the second portion 16Dfarther from the substrate 1 is formed by polishing such as CMP. Thesurface 16Ca of the first portion 16C farther from the substrate 1 isformed by etching such as ion beam etching. Etching for forming thesurface 16Ca is performed only on portions of the magnetic layers 161Pand 162P near the medium facing surface 30 after the top surfaces of themagnetic layers 161P and 162P are flattened by CMP, for example. It isthereby possible to perform this etching with precision. Therefore,according to the embodiment, it is possible to control the thickness ofthe first portion 16C, that is, the thickness of the pole layer 16 takenin the medium facing surface 30, with precision. Furthermore, it isthereby possible to control the track width with precision.

According to the embodiment, in particular, etching of the portions ofthe magnetic layers 161P and 162P is performed such that the second sideA2 of the end face of the pole layer 16 located in the medium facingsurface 30 is disposed at a height that falls within the range betweenthe height at which the top surface of the nonmagnetic metal layer 13 asinitially formed is located and the height at which the bottom surfacethereof is located. It is thereby possible to control the thickness ofthe pole layer 16 taken in the medium facing surface 30 and the trackwidth with precision.

According to the embodiment, the second portion 16D of the pole layer 16has a thickness greater than that of the first portion 16C. As a result,it is possible to introduce a magnetic flux of great magnitude to themedium facing surface 30 through the pole layer 16 while the thicknessof the pole layer 16 taken in the medium facing surface 30 is reduced.It is thereby possible to implement a sufficient overwrite property.

Flux leakage from the pole layer 16 is likely to occur in the portion ofthe pole layer 16 where the thickness changes, that is, in aneighborhood of the front end face 16Db. If the flux leaking from thisportion reaches the medium facing surface 30 and further leaks to theoutside from the medium facing surface 30, the effective track widthwill increase and/or the problems resulting from the skew will occur.According to the embodiment, the shield layer 20 has the portion locatedbetween the front end face 16Db and the medium facing surface 30 in theregion closer to the substrate 1 than the surface 16Da of the secondportion 16D of the pole layer 16 farther from the substrate 1.Therefore, the leakage flux from the portion of the pole layer 16 inwhich the thickness changes is taken in by the shield layer 20. It isthereby possible that the flux leaking from somewhere in the middle ofthe pole layer 16 is prevented from leaking to the outside from themedium facing surface 30.

According to the embodiment, the magnetic head comprises the yoke layer20B that touches the surface of the second portion 16D of the pole layer16 farther from the substrate 1. An end of the yoke layer 20B closer tothe medium facing surface 30 is located farther from the medium facingsurface 30 than the location of the boundary between the surfaces 16Daand 16Db of the pole layer 16. Therefore, the magnetic layer made up ofa combination of the pole layer 16 and the yoke layer 20B beingconsidered, the thickness of this magnetic layer is reduced by two stepsas the distance from the medium facing surface 30 decreases. As aresult, it is possible to introduce a magnetic flux of great magnitudeto the medium facing surface 30 while preventing saturation of fluxhalfway through the magnetic layer.

According to the embodiment, the top surface of the pole layer 16 bendsin the neighborhood of the medium facing surface 30. It is therebypossible to suppress generation of residual magnetization in thedirection orthogonal to the medium facing surface 30 in a portion of thepole layer 16 near the medium facing surface 30 after writing isperformed. As a result, it is possible to suppress the occurrence of aphenomenon in which data stored on the recording medium is erasedbecause of the residual magnetization in the pole layer 16 after writingis performed.

In the second embodiment, as in the first embodiment, the throat heightTH is the distance between the medium facing surface 30 and the point atwhich the gap layer 18 first bends when seen from the medium facingsurface 30, that is, the point at which the bottom surface of the firstlayer 20A first bends when seen from the medium facing surface 30. Inthe second embodiment the gap layer 18 and the nonmagnetic film 17 aredisposed between the pole layer 16 and the first layer 20A in the regionfarther from the medium facing surface than the point at which the gaplayer 18 first bends when seen from the medium facing surface 30.Consequently, flux leakage between the pole layer 16 and the shieldlayer 20 in this region is less, compared with the case in which thenonmagnetic film 17 is not provided. As a result, according to theembodiment, it is possible to introduce a magnetic flux of greatmagnitude to the medium facing surface 30 and it is thereby possible toimprove the overwrite property. The remainder of configuration, functionand effects of the second embodiment are similar to those of the firstembodiment.

MODIFICATION EXAMPLES

First and second modification examples of the second embodiment will nowbe described. FIG. 26A and FIG. 26B illustrate the first modificationexample. FIG. 26A shows a cross section of the main part of the magnetichead orthogonal to the medium facing surface and the substrate. FIG. 26Bshows a cross section of the main part of the magnetic head near themedium facing surface that is parallel to the medium facing surface. InFIG. 26A and FIG. 26B the portions closer to the substrate 1 than theencasing layer 12 are omitted.

In the first modification example the nonmagnetic film 17 is notprovided while the gap layer 18 is disposed on the surface 16Da of thesecond portion 16D of the pole layer 16. The remainder of configuration,function and effects of the first modification example are similar tothose of the magnetic head illustrated in FIG. 17 to FIG. 19 except thefunction and effects resulting from the nonmagnetic film 17.

FIG. 27A and FIG. 27B illustrate the second modification example. FIG.27A shows a cross section of the main part of the magnetic headorthogonal to the medium facing surface and the substrate. FIG. 27Bshows a cross section of the main part of the magnetic head near themedium facing surface that is parallel to the medium facing surface. InFIG. 27A and FIG. 27B the portions closer to the substrate 1 than theencasing layer 12 are omitted.

In the second modification example, as in the first modificationexample, the nonmagnetic film 17 is not provided while the gap layer 18is disposed on the surface 16Da of the second portion 16D of the polelayer 16. The magnetic head of the second modification example comprisesthe insulating layer 28 that covers at least part of the coil 23 inplace of the insulating layer 24 of FIG. 18. The insulating layer 28 ismade of photoresist, for example. The shield layer 20 of the secondmodification example comprises the second layer 20F in place of thesecond layer 20C, the coupling layer 20D and the third layer 20E of theFIG. 18. One of end faces of the second layer 20F closer to the mediumfacing surface 30 is located at a distance from the medium facingsurface 30. The second layer 20F is disposed to couple the first layer20A to the yoke layer 20B. The second layer 20F includes a portionlocated on a side of the at least part of the coil 23 covered with theinsulating layer 28, the side being opposite to the pole layer 16. Thesecond layer 20F may be made of any of CoFeN, CoNiFe, NiFe, and CoFe,for example. In the second modification example, the protection layer 27is disposed between the medium facing surface 30 and the end face of thesecond layer 20F closer to the medium facing surface 30. The protectionlayer 27 of the second modification example corresponds to the secondnonmagnetic layer of the invention. It is preferred that the protectionlayer 27 have a thermal expansion coefficient smaller than that of theinsulating layer 28. The remainder of configuration, function andeffects of the magnetic head of the second modification example aresimilar to those of the first modification example.

It is possible to provide modification examples of the second embodimentthat are similar to the first to third modification examples of thefirst embodiment.

Third Embodiment

Reference is now made to FIG. 28 and FIG. 29 to describe a magnetic headand a method of manufacturing the same of a third embodiment of theinvention. FIG. 28 is a perspective view illustrating a portion of themagnetic head of the third embodiment in a neighborhood of the mediumfacing surface. FIG. 29 is a top view illustrating a portion of theshield layer of the magnetic head of the third embodiment.

In the third embodiment, as shown in FIG. 29, the first layer 20A of theshield layer 20 incorporates two side portions 20A2 and 20A3 located atpositions along the direction of width outside the end face located inthe medium facing surface 30 when seen from the medium facing surface30. A portion of the first layer 20A located between the two sideportions 20A2 and 20A3 is called a middle portion 20A1. The middleportion 20A1 has the end face 20A10 located in the medium facing surface30. Respective end faces 20A20 and 20A30 of the side portions 20A2 and20A3 each of which is closer to the medium facing surface 30 are locatedat a distance from the medium facing surface 30. As shown in FIG. 28,the nonmagnetic layer 21 disposed around the first layer 20A is locatedbetween the medium facing surface 30 and the end faces 20A20 and 20A30.

The distance between the medium facing surface 30 and the end faces20A20 and 20A30 of the side portions 20A2 and 20A3 gradually increasesfrom the boundary between the middle portion 20A1 and the side portions20A2 and 20A3 toward the outside along the direction of width, and thenmaintains a specific distance. That is, the end faces 20A20 and 20A30respectively incorporate parallel portions 20A21 and 20A31 that areparallel to the medium facing surface 30, and sloped portions 20A22 and20A32 that connect the parallel portions 20A21 and 20A31 to the end face20A10 of the middle portion 20A1.

The width W1 of the end face of the first layer 20A located in themedium facing surface 30, that is, the end face 20A10 of the middleportion 20A1, is equal to or greater than the track width. The width W1preferably falls within a range of 0.1 to 10 μm inclusive. The distanceW2 from the boundary between the parallel portion 20A21 and the slopedportion 20A22 to the boundary between the parallel portion 20A31 and thesloped portion 20A32 preferably falls within a range of 1.0 to 11 μminclusive.

The distance H1 between the medium facing surface 30 and the parallelportions 20A21 and 20A31 preferably falls within a range of 0.2 to 0.8μm inclusive. The distance H2 between the medium facing surface 30 andthe end face of the second layer 20C closer to the medium facing surface30 preferably falls within a range of 0.2 to 0.8 μm inclusive. Thedistance H3 between the medium facing surface 30 and the end face of thethird layer 20E closer to the medium facing surface 30 preferably fallswithin a range of 0.2 to 0.8 μm inclusive.

It is acceptable that the end faces 20A20 and 20A30 of the side portions20A2 and 20A3 do not incorporate the sloped portions 20A22 and 20A32. Inthis case, the middle portion 20A1 has two side faces that connect theend face 20A10 to the parallel portions 20A21 and 20A31. These two sidefaces are orthogonal to the medium facing surface 30.

In the third embodiment, the first layer 20A of the shield layer 20incorporates the two side portions 20A2 and 20A3 located at positionsalong the direction of width outside the end face located in the mediumfacing surface 30 when seen from the medium facing surface 30. As aresult, according to the embodiment, it is possible to make the area ofthe end face of the shield layer 20 exposed in the medium facing surface30 smaller, compared with the first embodiment. It is thereby possibleto define the throat height TH with higher accuracy and to suppressprotrusion of the end portion of the shield layer 20 located closer tothe medium facing surface 30 resulting from the heat generated by thecoil 23.

In the third embodiment, the end face of each of the second layer 20Cand the third layer 20E that is closer to the medium facing surface 30may be located in the medium facing surface 30. In this case, too, ascompared with the magnetic head of FIG. 32, it is possible to make thearea of the end face of the shield layer 20 exposed in the medium facingsurface 30 smaller, so that it is possible to define the throat heightTH with accuracy and to suppress protrusion of the end portion of theshield layer 20 located closer to the medium facing surface 30 resultingfrom the heat generated by the coil 23. However, to make the most ofthese effects, it is preferred that the end face of each of the secondlayer 20C and the third layer 20E closer to the medium facing surface 30be located at a distance from the medium facing surface 30.

For conventional shield-type heads, there are some cases in which such aphenomenon arises that there occurs attenuation of signals written onone or more tracks adjacent to the track that is a target of writing orreading in a wide range along the direction of track width. (Thephenomenon will be hereinafter called wide-range adjacent track erase.)It is assumed that the wide-range adjacent track erase results from amagnetic flux passing through the end face of the shield layer exposedin the medium facing surface.

In the third embodiment only the end face 20A10 of the middle portion20A1 of the first layer 20A of the shield layer 20 is located in themedium facing surface 30. In addition, the end faces 20A20 and 20A30 ofthe side portions 20A2 and 20A3 are located at a distance from themedium facing surface 30. As a result, according to the embodiment, itis possible to make the width of the end face of the first layer 20Aexposed in the medium facing surface 30 smaller, compared with the casein which the entire end face of the first layer 20A closer to the mediumfacing surface 30 is exposed in the medium facing surface 30.Furthermore, according to the embodiment, it is possible to adjust theamount of magnetic flux passing through the end face of the shield layer20 exposed in the medium facing surface 30 by controlling the shape ofthe first layer 20A. These features of the embodiment make it possibleto suppress the wide-range adjacent track erase.

The remainder of configuration, function and effects of the thirdembodiment are similar to those of the first embodiment including themodification examples.

Fourth Embodiment

Reference is now made to FIG. 30 and FIG. 31 to describe a magnetic headand a method of manufacturing the same of a fourth embodiment of theinvention. FIG. 30 is a cross-sectional view illustrating a portion ofthe magnetic head of the embodiment. FIG. 30 illustrates a cross sectionorthogonal to the medium facing surface and the substrate. In FIG. 30the portions closer to the substrate than the encasing layer areomitted. FIG. 31 is a top view of the shield layer of the magnetic headof the embodiment.

In the fourth embodiment, as in the second embodiment, as shown in FIG.30, the pole layer 16 incorporates: a first portion 16C having the endface located in the medium facing surface 30; and a second portion 16Dlocated farther from the medium facing surface 30 than the first portion16C and having a thickness greater than that of the first portion 16C.The thickness of the first portion 16C does not change in accordancewith the distance from the medium facing surface 30.

The surface (the top surface) 16Ca of the first portion 16C farther fromthe substrate 1 is located closer to the substrate 1 than the surface(the top surface) 16Da of the second portion 16D farther from thesubstrate 1. The second portion 16D has the front end face 16Db thatcouples the surface 16Ca of the first portion 16C farther from thesubstrate 1 to the surface 16Da of the second portion 16D farther fromthe substrate 1.

An end of the nonmagnetic film 17 closer to the medium facing surface 30is located at a position corresponding to a corner portion formedbetween the surfaces 16Da and 16Db.

The magnetic head of the fourth embodiment comprises the insulatinglayer 28 that covers at least part of the coil 23 in place of theinsulating layer 24 of FIG. 18. The insulating layer 28 is made ofphotoresist, for example. The shield layer 20 comprises the second layer20F in place of the second layer 20C, the coupling layer 20D and thethird layer 20E of the FIG. 18. One of end faces of the second layer 20Fcloser to the medium facing surface 30 is located at a distance from themedium facing surface 30. The second layer 20F includes a portionlocated on a side of the at least part of the coil 23 covered with theinsulating layer 28, the side being opposite to the pole layer 16. Thesecond layer 20F may be made of any of CoFeN, CoNiFe, NiFe, and CoFe,for example. The protection layer 27 is disposed between the mediumfacing surface 30 and the end face of the second layer 20F closer to themedium facing surface 30. The protection layer 27 of the fourthembodiment corresponds to the second nonmagnetic layer of the invention.It is preferred that the protection layer 27 have a thermal expansioncoefficient smaller than that of the insulating layer 28.

The shield layer 20 has a portion that is sandwiched between the frontend face 16Db and the medium facing surface 30 and that is located in aregion closer to the substrate 1 than the surface 16Da of the secondportion 16D farther from the substrate 1. To be specific, this portionis a portion of the first layer 20A of the shield layer 20 closer to thesubstrate 1 than the surface 16Da. An end of the yoke layer 20B of theshield layer 20 located closer to the medium facing surface 30 islocated farther from the medium facing surface 30 than the boundarybetween the surfaces 16Da and 16Db of the pole layer 16.

In the fourth embodiment, as shown in FIG. 31, the first layer 20Aincorporates: a middle portion 20A4 including a portion that facestoward the pole layer 16 with the gap layer 18 disposed in between; andtwo side portions 20A5 and 20A6 disposed outside the middle portion 20A4along the direction of width.

The middle portion 20A4 has an end face located in the medium facingsurface 30. The side portions 20A5 and 20A6 have respective end faceseach of which is located closer to the medium facing surface 30. Ofthese end faces, portions contiguous to the end face of the middleportion 20A4 are located in the medium facing surface 30, and theremaining portion is located at a distance from the medium facingsurface 30.

The maximum length of the side portions 20A5 and 20A6 taken in thedirection orthogonal to the medium facing surface 30 is greater than themaximum length of the middle portion 20A4 taken in the directionorthogonal to the medium facing surface 30. In the example shown in FIG.31, the length of the middle portion 20A4 taken in the directionorthogonal to the medium facing surface 30 is uniform. The length H11 ofthe middle portion 20A4 falls within a range of 0.1 to 0.3 μm, forexample. The width W11 of the middle portion 20A4 falls within a rangeof 0.3 to 5.0 μm, for example.

The middle portion 20A4 may have a portion located above the nonmagneticfilm 17. Alternatively, it is acceptable that the middle portion 20A4does not have any portion located above the nonmagnetic film 17. If themiddle portion 20A4 has the portion located above the nonmagnetic film17, the throat height TH is the distance from the medium facing surface30 to the point at which the gap layer 18 first bends when seen from themedium facing surface 30. If the middle portion 20A4 has no portionlocated above the nonmagnetic film 17, the throat height TH is thesmaller one of the length H11 of the middle portion 20A4 and thedistance from the medium facing surface 30 to the point at which the gaplayer 18 first bends when seen from the medium facing surface 30.

An end face of the second layer 20F closer to the medium facing surface30 is located at a distance from the medium facing surface 30. Thedistance H21 between the medium facing surface 30 and the end face ofthe second layer 20F closer to the medium facing surface 30 falls withina range of 0.3 to 0.9 μm, for example.

The second layer 20F is not connected to the middle portion 20A4 of thefirst layer 20A, but connected to the side portions 20A5 and 20A6 of thefirst layer 20A. In FIG. 31 numerals 41 and 42 indicate through holesfor connecting the second layer 20F to the side portions 20A5 and 20A6.The second layer 20F is connected to the pole layer 16 at a point awayfrom the medium facing surface 30. In FIG. 31 numeral 43 indicates athrough hole for connecting the second layer 20F to the pole layer 16.

If the magnetic head has such a configuration that the second layer 20Fis connected to the portion of the first layer 20A that faces toward thepole layer 16 with the gap layer 18 in between, it is required toincrease the length of the above-mentioned portion of the first layer20A taken in the direction orthogonal to the medium facing surface 30 tosome extent. However, this will cause a possibility that it isimpossible to obtain a sufficient overwrite property. In addition, ifthe length of the above-mentioned portion of the first layer 20A takenin the direction orthogonal to the medium facing surface 30 is great,there also occurs an increase in the distance from the medium facingsurface 30 to the junction between the second layer 20F and the polelayer 16 (the distance may be hereinafter called the yoke length). Anincrease in yoke length results in a possibility of degradation in writecharacteristics in a high frequency range. To prevent this, it ispossible to reduce the yoke length by reducing the pitch of the turns ofthe coil 23. In this case, however, the resistance of the coil 23 willbe increased.

In the fourth embodiment, as mentioned above, the second layer 20F isnot connected to the middle portion 20A4 of the first layer 20A, butconnected to the side portions 20A5 and 20A6 of the first layer 20A. Asa result, according to the embodiment, it is possible to connect thefirst layer 20A to the second layer 20F with accuracy while reducing thelength H11 of the middle portion 20A4. It is thereby possible to improvethe overwrite property and to prevent an increase in yoke length and anincrease in resistance of the coil 23.

In the fourth embodiment the shield layer 20 may incorporate the secondlayer 20C, the coupling layer 20D and the third layer 20E of FIG. 18 inplace of the second layer 20F. In this case, the second layer 20C is notconnected to the middle portion 20A4 of the first layer 20A butconnected to the side portions 20A5 and 20A6 of the first later 20A.

In the fourth embodiment the pole layer 16 may have a shape the same asthat of the first embodiment. In the fourth embodiment, as in the secondmodification example of the second embodiment, it is not absolutelynecessary to provide the nonmagnetic film 17. The remainder ofconfiguration, function and effects of the fourth embodiment are similarto those of the second embodiment.

The present invention is not limited to the foregoing embodiments butmay be practiced in still other ways. For example, the shield layer 20of the second embodiment may have a configuration the same as that ofthe third embodiment.

A coil wound around the pole layer 16 in a helical manner may beprovided in any of the embodiments in place of the flat-whorl-shapedcoils 9 and 23.

In the foregoing embodiments, at least a portion of the pole layer 16 isformed in the groove 12 a of the encasing layer 12. However, the polelayer of the invention is not limited to the one formed in such a mannerbut may be formed otherwise. For example, the pole layer may be formedby patterning a magnetic layer by etching, or may be formed by plating.

While the magnetic head disclosed in the embodiment has such aconfiguration that the read head is formed on the base body and thewrite head is stacked on the read head, it is also possible that theread head is stacked on the write head.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

1. A magnetic head for perpendicular magnetic recording comprising: amedium facing surface that faces toward a recording medium; a coil forgenerating a magnetic field corresponding to data to be written on therecording medium; a pole layer having an end face located in the mediumfacing surface, allowing a magnetic flux corresponding to the fieldgenerated by the coil to pass therethrough, and generating a writemagnetic field for writing the data on the recording medium by means ofa perpendicular magnetic recording system; a shield layer having an endface located in the medium facing surface and having a portion that isaway from the medium facing surface and coupled to the pole layer; and agap layer made of a nonmagnetic material and disposed between the polelayer and the shield layer, wherein: in the medium facing surface, theend face of the shield layer is located forward of the end face of thepole layer along a direction of travel of the recording medium with aspecific space created by a thickness of the gap layer; at least part ofthe coil is disposed between the pole layer and the shield layer andinsulated from the pole layer and the shield layer; the end face of thepole layer located in the medium facing surface has a side locatedadjacent to the gap layer, the side defining a track width; and theshield layer incorporates: a first layer located adjacent to the gaplayer and having the end face located in the medium facing surface; anda second layer located on a side of the first layer farther from the gaplayer; and the first layer has two portions located at positions along adirection of width outside the end face located in the medium facingsurface when seen from the medium facing surface, and an end face ofeach of the two portions closer to the medium facing surface is locatedat a distance from the medium facing surface, the magnetic head furthercomprising: an insulating layer made of an insulating material anddisposed around the at least part of the coil; and a nonmagnetic layermade of a nonmagnetic material and disposed around the first layer. 2.The magnetic head according to claim 1, wherein the nonmagnetic layer ismade of an inorganic insulating material.
 3. The magnetic head accordingto claim 1, wherein the at least part of the coil is located fartherfrom the pole layer than a surface of the first layer farther from thepole layer.
 4. The magnetic head according to claim 1, furthercomprising a nonmagnetic film made of a nonmagnetic material anddisposed between the pole layer and the second layer, wherein: thenonmagnetic film has an end closer to the medium facing surface that islocated at a distance from the medium facing surface; and the firstlayer has a portion located between the nonmagnetic film and the secondlayer.